In a medium saucepan, combine the rinsed quinoa and water. Bring to a boil over medium-high heat.
Once boiling, reduce heat to low, cover, and simmer for 15 minutes or until quinoa is tender and water is absorbed.
Remove quinoa from heat and let it sit covered for 5 minutes, then fluff with a fork.
While quinoa cooks, preheat a grill pan or skillet over medium-high heat.
In a small bowl, mix olive oil, dried oregano, garlic powder, salt, and black pepper.
Brush the chicken breasts with the olive oil mixture evenly on both sides.
Grill the chicken for 6-8 minutes per side or until cooked through and internal temperature reaches 165°F (74°C).
Remove chicken from heat and let rest for 5 minutes, then slice into strips.
In a small bowl, combine Greek yogurt, lemon juice, fresh dill, minced garlic, salt, and black pepper to make tzatziki sauce. Mix well and refrigerate until ready to serve.
Divide the cooked quinoa evenly among four bowls.
Top each bowl with sliced grilled chicken, cherry tomatoes, diced cucumber, red onion, kalamata olives, and crumbled feta cheese.
Drizzle tzatziki sauce over each bowl and garnish with chopped fresh parsley.
Serve immediately and enjoy your high protein chicken Greek bowl.